1. Field of the Invention
This invention relates generally to navigation systems, and more particularly to a portable electronic navigation apparatus and method utilizing universal latitude and longitude coordinates of geographic points and landmarks for aiding in the determination of a specific geographical destination and the distance thereof relative to landmark data input by the user.
2. Brief Description of the Prior Art
Often a traveler in a vehicle, boat, bicycle, or on foot needs help to get to his or her destination. If the traveler has a map, the map may not have sufficient information to be able to pinpoint the current location, because most maps present substantially fewer than all population centers (i.e., towns, villages, municipalities, and cities). Also, maps often leave the reader lost somewhere within a 25 square mile area after looking up the X and Y coordinates for a town not actually depicted presented by a dot and name on the map. Also, the vast amount of detail included in a tiny area on many maps makes it hard to find a specific place even if it is presented by a dot and name on the map.
Computer navigational devices are known in the art. There are several patents which disclose various navigational aids and systems designed to be used by travelers in vehicles, most of which depend upon vehicle motion sensors for their operation.
Tanaka et al, U.S. Pat. No. 4,608,656 discloses a road map display system coupled with a vehicle sensor wherein vehicle position and direction is graphically represented as a mark on a map. A digital memory stores digitized road map data in the form of points on a map relative to an X and Y coordinate system, the vehicle sensor detects vehicle placement and distance traveled from a starting point and produces a signal representing the vehicle location relative to the coordinates, a scale selector enlarges the map when the vehicle is in a certain distance of a preselected point and produces a second signal representative of the scale. The digitized map data is transformed by a display memory into a second coordinate system which is displayed about the vehicle position.
Nakamura, U.S. Pat. No. 4,660,037 discloses a road map display system coupled with a vehicle sensor wherein the current vehicle position and direction is graphically represented on a map. A digital memory stores digitized road map data in the form of digital information taken pixel by pixel in the raster mode (optical disc) and the vehicle sensor detects the current travel distance and direction from a starting point and produces a signal representing the vehicle location in two-dimensional (X-Y) coordinates. A regeneration unit (laser) reads out the geographical information from time to time during travel. The digitized map data is transformed by a display memory into a second coordinate system which graphically displays a mark for the current location, a mark for the direction of travel, and a mark indicating the accumulated path of travel.
Tsujii, U.S. Pat. No. 4,679,147 discloses a road map display system coupled with several vehicle sensors wherein a cathode ray tube displays road map information and vehicle tracing information with the vehicle superimposed on the map. A bearing sensor utilizes magnetism and provides analog quantities representative of the X-Y coordinates. An optical fiber sensor detects the vehicle running direction and provides a relative bearing. A vehicle speed sensor generates pulses which provide a signal representative of the vehicle running distance. The data is stored in memory and a controller selects information corresponding to the current location for display. The controller sets specified circular areas centered on respective crossings on the road map, detects arrival of the of the vehicle at the entrance to a particular area, and gives a voice instruction for running the vehicle at the crossing.
Hanabusa et al, U.S. Pat. No. 4,737,927 discloses a road map display system coupled with several vehicle sensors which stores map data such as rivers, roads, streets, principle buildings, etc., and various corresponding name information and only the selected name information is displayed on the screen with the map using its name or capital letter. It includes a vehicle heading sensor and distance sensor, and a control unit responsive to the signals for displaying a map on the display. The map data is divided into sections with corresponding names. It is only necessary to search the name information group in the relevant section.
Haeussermann, U.S. Pat. No. 4,733,356 discloses a hand held control device for vehicle route guidance which may be used alone or installed in an on-board computer system. The hand held unit comprises a plug-in compartment which receives a road network memory chip, a route computer, operating system, and its own display, which allows preselection of the route functions outside the vehicle. The system functions are divided into "pre-trip" and "during the trip". Pre-trip functions performed with the hand-held unit are: starting point and destination, calculation of the optimum route, adaption of the route to traffic conditions or personal requirements, and preselecting the route in which automatic route indication is to be carried out. During the trip functions are carried out when the hand-held device is plugged into the on-board computer.
The present invention is distinguished over the prior art in general, and these patents in particular by a portable electronic navigation apparatus and method which utilizes universal latitude and longitude coordinates of geographic points and landmarks for determining current location or a specific destination and the distance and bearing thereof relative to landmark data input by the user. Latitude and longitude of population centers (e.g., cities, towns), major buildings, airports, and other landmarks in a geographical area are stored in a first memory. Latitudinal and longitudinal data for roadways in the area are stored in a second memory. A third permanent memory stores programs to; calculate the distance between two known points; look up and retrieve stored information; store and erase data upon the user's instruction; accept corrections to stored data; and to display the data on a screen in relation to its latitude and longitude along with name, mileage, and bearing or destination data corresponding to the related geographical feature or landmark. Destination, current or hypothetical location, latitude and longitude adjustments, other data, and requests for navigational information is input by a keyboard. Roads, population centers, airports, buildings, other landmarks, mileages, and bearings or directions according to the operator's request is displayed visually or vocally. The user may specify a radius around the current or destination location, and receive the distance between the destination and any other geographical feature, landmark, or roadway within the designated radius or within the designated path width.
The present invention does not require inputting settings into the system before making use of it, unlike other navigational systems and is significantly less costly to build than systems requiring the attachment of bearing and speed sensors to a moving vehicle, reading the results into the device, and computing the present location and heading from such ever-changing data. The sensors also make these other systems non-portable.